The filtering of fluids has been done by both mechanical and electrostatic methods. In mechanical filtering, it is difficult to filter out particles having dimensions of less than 5 to 10 microns because of the small size of the particles.
Electrostatic filtering has been accomplished as defined in U.S. Pat. No. 4,594,138, issued Jun. 10, 1986. The filter described in this patent filters the fluid through a mechanical filter media, and also passing the fluid through perforated electrodes which are oppositely polarized by positive and negative charges. Because of the mechanical structure of the filter apparatus, it is not practical to change out and/or clean the mechanical filter media.